In this paper we present our work on designing and implementing an NS3 model for MultiPath TCP (MPTCP). Our MPTCP model closely follows MPTCP specifications, as described in RFC 6824, and supports TCP NewReno loss recovery on a per subflow basis. Subflow management is based on MPTCP's kernel implementation. We briefly describe how we integrate our MPTCP model with NS3 and present example simulation results to showcase its working state.